feat: added bits & bytes handeling functions and macros

kernel/include/kstdlib.h

@@ -1,9 +1,80 @@
 #ifndef __K_STDLIB
 #define __K_STDLIB
 
-#define unlikely(x) __builtin_expect(x, 0)
-#define likely(x) __builtin_expect(x, 1)
+#include <ktypes.h>
 
+#define unlikely(x) __builtin_expect(x, 0)
+#define likely(x)   __builtin_expect(x, 1)
+
+/** @brief Ignore unused variable/static function.*/
 #define IGNORE_UNUSED(x) ((void)x)
 
-#endif
+#define BITS_PER_BYTE 8
+
+/**
+ * @brief Convert bits to bytes.
+ *
+ * @param [in] n - given number of bits.
+ * @return number of bytes needed for containing n bits.
+ */
+static inline usize bits_to_bytes(usize n)
+{
+    // assuming that a byte contains 8 bits
+    return (n + 7) >> 3;
+}
+
+/**
+ * @brief Convert bytes to bits.
+ *
+ * @param [in] n - given number of bytes.
+ * @return number of bits in n bytes.
+ */
+static inline usize bytes_to_bits(usize n)
+{
+    // assuming that a byte contains 8 bits
+    return n << 3;
+}
+
+/**
+ * @brief Get number of bits in value.
+ *
+ * @param [in] x - given value to count.
+ * @return number of bits in value.
+ */
+#define BITS_PER_TYPE(x) (bytes_to_bits(sizeof(x)))
+
+/**
+ * @brief Set the specific bit of given value.
+ *
+ * @param [out] value - given value to change.
+ * @param [in] pos - given bit position to set.
+ */
+static inline void set_bit(u32* value, i32 pos)
+{
+    *value |= (1U << pos);
+}
+
+/**
+ * @brief Clear the specific bit of given value.
+ *
+ * @param [out] value - given value to change.
+ * @param [in] pos - given bit position to clear.
+ */
+static inline void clear_bit(u32* value, i32 pos)
+{
+    *value &= ~(1U << pos);
+}
+
+/**
+ * @brief Get the specific bit of given value.
+ *
+ * @param [in] value - given value to test.
+ * @param [in] pos - given bit position to test.
+ * @return true if the bit is set, false otherwise.
+ */
+static inline bool test_bit(u32 value, i32 pos)
+{
+    return (value & (1U << pos)) != 0;
+}
+
+#endif /* __K_STDLIB */